This invention relates to a hydraulic circuit for a hydraulically driven vehicle and in particular to an inching brake control circuit of a hydraulically driven vehicle in which a variable displacement hydraulic pump and a hydraulic motor driven therey is connected with each other in a closed circuit.
A conventional inching brake control for a hydraulically driven vehicle involves following disadvantages.
First, a parking brake is not automatically applied when a speed change lever is returned or shifted to a neutral position. Instead, the parking brake must be applied manually after shifting the speed change lever to the neutral position. Therefore, it is very dangerous if and when an operator has forgotten to apply the parking brake manually.
Secondly, even if an inching brake control involves such a circuit that enables a parking brake to be automatically applied when a speed change lever is shifted to the neutral position, it is desirable for a vehicle to be equipped with an emergency brake circuit which enables the vehicle to be braked or retarded when the vehicle is being towed with its engine being not operated.
Conventionally, however, there has been no inching brake control for a hydraulically driven vehicle which involves the above braking circuit.